CMAKE not honor openbmp.conf installation path

[v1shnya]

Hi Tim,

during the standard build process I see that the conf file is not being placed where it should be

$ cmake -DCMAKE_INSTALL_PREFIX:PATH=/usr ../
$ make
$ sudo make install
Consolidate compiler generated dependencies of target openbmpd
[100%] Built target openbmpd
Install the project...
-- Install configuration: ""
-- Installing: /usr/bin/openbmpd
-- Up-to-date: **/usr/etc/openbmp/openbmpd.conf**

After making installation path absolute, not reletative it's fixed
install(FILES openbmpd.conf DESTINATION **/etc/openbmp/** COMPONENT config)

And, we get

$ sudo make install
Consolidate compiler generated dependencies of target openbmpd
[100%] Built target openbmpd
Install the project...
-- Install configuration: ""
-- Installing: /usr/bin/openbmpd
-- Up-to-date: **/etc/openbmp/openbmpd.conf**